The invention relates to pipes and tubular conduits, but more particularly, the invention relates to flexible hose with means disposed in the hose duct that facilitates retaining the hose in a desired curve contour.
Radiator hose and heater hose are used extensively by the automobile industry. Radiator hose is used for ducting a cooling fluid between an engine block and radiator while heater hose is used for ducting warm fluids between an engine block and a passenger compartment heater element. Some radiator and heater hose are molded with compound curves to facilitate fluid ducting requirements dictated by the automobile manufacturers. Oftentimes, such hose (especially radiator hose) must be molded with several compound curves and ends of different diameters. The complex curved shapes are oftentimes required to avoid interference with engine system components such as V-belts, alternators, air conditioning compressors, or power steering pumps. Curved hose is configured by manually placing hose stock material over a curved mandrel and then heat setting the stock material while in the curved shape. Curved hose having a center line length generally beyond 36 inches are typically not produced because of the difficulty of manually placing the hose product on and removing it from a curved mandrel. Of course, the number and degree of compound bends affects the difficulty of placing and removing a hose from a mandrel.
While curved or preformed hose solves routing problems for an original equipment manufacturer, it creates inventory problems for an aftermarket hose distributor. The aftermarket hose distributor (e.g., a filling station) may find it economically unfeasible to attempt to stock curved hose for all applications. Corrugated hose has become a popular replacement for curved hose to the small hose distributor because he can carry only a small corrugated hose inventory that is suitable as a substitute for a plurality of differently configured curved hoses. For example, one length of corrugated hose may be an effective substitute for ten or more curved hose configurations.
Corrugated hose usually has two sleeve ends or "cuffs" which are interconnected by a corrugated hose wall. The corrugation may be in the form of helical convolutions or annular rings. The corrugations permit a folding of the hose wall in a manner which avoids kinking. However, some bent hose configurations require a collapse resistant reinforcement located near the corrugations. For example, such a reinforcement may be in the form of a helical spring disposed at the internal or external diameters of the hose wall, or the spring may be embedded in the corrugation. A hose having annular rings may require wire loops disposed at the internal or external diameters of the convolutions, or be completely embedded within the wall of the hose. Examples of corrugated hose are disclosed in the following U.S. Patents which are hereby incorporated by reference as showing various types of corrugated hose: U.S. Pat. Nos. 2,936,812; 3,050,087; 3,194,705; 3,379,805.
Although corrugated hose is an acceptable substitute for many curved hose applications, it has not been a "cure all" substitute for all curved hose applications. Corrugated hose tends to take a symmetrical curved shape as the ends of the hose are positioned in parallel and/or angular misalignment. For example, a hose may be shaped to an "S" bend but both loops of the "S" tend to have the same bend radius. Many curved hose applications require unsymmetrical shapes to avoid interference with engine components. In such situations, a corrugated type hose may be unsuitable because it cannot readily support itself in compound curves at various bend radii around an obstacle.
Various hose inserts have been developed as hose kink preventers or as hose coiling devices. Examples of such inserts appear in U.S. Pat. Nos. 2,640,502 and 3,610,289. The inserts maintain the hose at a constant bend radius in the case of extensible coiled hose, or prevent a hose from kinking as it is flexed to various bend radii. While hose inserts are known in the art, they are not adapted to maintain a hose in a fixed straight or curved configuration.